Feature request: integrate Pipewire virtual surround filter (equal to Windows Sonic for Headphones)

[ahydronous]

By adding this Pipewire sink filter (plus adding a toggle in the SteamOS settings), you could have virtual surround audio on headphones and stereo speakers. It has been tested on Deck (via desktop mode) and works.

https://gitlab.freedesktop.org/pipewire/pipewire/-/blob/master/src/daemon/filter-chain/sink-virtual-surround-5.1-kemar.conf

It might even be possible to add a 7.1 filter, or for Valve to develop a bespoke tweaked filter optimized for games. This would be equivalent to Windows Sonic / Dolby Atmos for Headphones / DTS for Headphones.